Caster wheels and the like are notorious for inadvertently swiveling or gliding on the floor or other surface when in use and in a locked (and/or interlocked) configuration. This is problematic when the caster wheels or the like are those of a hoist or the like, potentially supporting a heavy load. If a caster swivels and a hoist shifts, the load can be dropped, potentially injuring a worker and/or damaging property. Thus, the use of failsafe devices is imperative.
To date, most caster locks have consisted of mechanisms that prevent the rotation of a caster wheel about its axle or housings that otherwise arrest the rotation of the caster wheel. For example, U.S. Pat. No. 5,829,096 provides a caster that includes a wheel rotatable about a wheel axis of rotation, a housing, a locking arm linked to the housing, and a locking bar linked to the housing. The housing includes a housing side wall and a housing detent formed in the housing side wall. The locking arm is movable between an unlocked position to permit the wheel to rotate about its wheel axis of rotation and a locked position to prevent or substantially restrict rotation of the wheel about its wheel axis of rotation. The locking arm is linked to the wheel so that movement of the locking arm between the locked and unlocked positions moves the wheel. The locking arm includes a locking arm side wall and a flared portion formed in the locking arm side wall and extending outwardly toward the housing side wall, the flared portion is engaged with the housing detent when the locking arm is in the locked position and disengaged from the housing detent when the locking arm is in the unlocked position. The locking bar includes a brake facing toward the wheel and engaging the wheel when the locking arm is situated in the locked position to prevent or substantially restrict rotation of the wheel about its wheel axis of rotation. The brake is an indentation formed in the locking bar.
Similarly, US 2006/0032015 provides a simple, inexpensive wheel lock suitable for use with many single or multiple wheel casters. Generally speaking, a known conventional caster has an integrally formed frame including a caster holder that has a curved fender and one or two wheels positioned below the curved fender. A wheel lock according to an embodiment of the invention is a curved piece of semi-rigid material that fits tightly enough into the space between the fender and the wheel to prevent the wheel from rolling. The wheel lock can be made to have an optional tab on the outer edge that permits easy positioning of the wheel lock and facilitates its removal.
Other caster locks have consisted of mechanisms in which a caster wheel is disposed to arrest the rotation of the caster wheel. For example, U.S. Pat. No. 5,210,903 provides that the roller of a caster mounting an article of furniture is lodged in an upwardly opening diametral groove in a flat circular caster stop having a central aperture in such slot and opposed ramps in the slot sloping oppositely upward with a gentle incline onto which a caster roller can roll from such central aperture.
Similarly, U.S. Pat. No. 5,513,727 provides a circumferential chock including opposing jaw members each having a chocking wall for engaging a wheel integrally joined by a hinge for providing movement of the jaw members in relation to each other between an open position for receiving a wheel and a substantially closed position circumferentially engaging the chocking walls with the wheel for braking a wheel against rolling, swiveling, and sliding.
However, none of these conventional devices adequately prevents a caster wheel from inadvertently swiveling or gliding on a floor or other surface when in use and in a locked configuration. Thus, worker injury and/or property damage are still significant issues.